Stevia rebaudiana is a plant which is known to contain sweet tasting compounds, including stevioside and rebaudioside A. These compounds are currently being used as sugar substitutes in a number of foodstuffs, including soft drinks. A detailed report regarding their safety, toxicology and metabolism may be found in Food and Chemical Toxicology 2008 Vol. 46(7), Supplement 1, where the entire supplement is devoted to rebaudioside A as used in food and beverages. Stevioside and rebaudioside A are metabolized by the mammalian intestinal tract into the aglycone steviol, a compound which is not sweet.
Today, it is important to look healthy and a tanned skin is always a sign of good health. One method of obtaining a tan is to expose skin to UV radiation causing direct DNA damage to the skin, which the body naturally combats and seeks to repair. In the process of repairing the damage and protect the skin, the body creates and releases the brown-colored pigment called melanin into the skin's cells, which gives the skin a darker tone. Melanin is produced by cells called melanocytes and protects the body from direct and indirect DNA damage by absorbing an excess of solar radiation. However, as exposure to UV radiation may have detrimental health effects such as sunburn or even skin cancer many people prefer alternatives which can produce a tanning result without exposure to ultraviolet radiation.
Numerous efforts have been made to identify drugs or other biomolecules that can be orally ingested and that will safely accomplish either or both of the following: (i) cause a tanning (also referred to as darkening of the color/tint/tone; pigmentation; or similar terms) of the skin, in a manner that looks like a healthy and natural suntan, while reducing or eliminating the need to spend hours in direct sunlight or in front of ultraviolet lamps; and/or, (ii) reduce the risk of a sunburn.
However, as the current products used for oral tanning do not deliver satisfactory results there is an ongoing need in the art for compositions which can enhance the natural tan of skin by stimulating the intrinsic melanin formation of a human being and which can be orally ingested.